The electrical voltage generally used in houses ranges from 110 to 220 volt, which is not deemed so high that the grounding system is easily ignored. The grounding material commonly used is a steel rod electroplated with copper, which is buried 30-100 cm deep under the ground and the lighting rod conductor is made of a plate of copper welded with a copper rod which is exposed above ground as shown in FIG. 1. The release electrode of such grounding is not always buried deep under the ground where much concrete, sand, stone or gravel lie. These materials are bad conductors. In addition, if the grounding electrode is located in a dry place and any current leakage occurs, a shock will result from touching the grounding wire because of the potential existing between the grounding wire and the ground. In other words, the grounding wire is capable of releasing some but not all current which results from imperfect grounding. What's more, when current leakage is found, it is impossible to know which electric appliance is leaking, and even if a great deal of leakage should occur, the power cannot be shut off automatically.
The present invention is to improve the aforementioned problems in order to avoid any loss of life and property caused by an electric leakage.